Phase 3 Trials Launched for AZ SARS-CoV2 Vaccine Candidate

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The investigational coronavirus disease 2019 (COVID-19) vaccine candidate being developed by AstraZeneca has expanded into a phase 3 clinical trial, according to a company press release.

The vaccine, AZD1222, which was co-invented by the University of Oxford and its affiliated company Vaccitech, is being developed via a viral vector platform, which takes an infectious human virus (ie, adenovirus) and genetically modifies it to produce the COVID-19 antigen and perhaps also to attenuate the viral vector. The same process was used to develop the Ebola vaccine.

Plans for diversity, age stratification

The US trial is enrolling up to 30,000 adults aged 18 years or older from diverse racial, ethnic and geographic groups who are healthy or have stable underlying medical conditions, including those living with HIV, and who are at increased risk of infection from the SARS-CoV-2 virus.

The trial will randomize participants to receive 2 doses of either AZD1222 or a saline control, 4 weeks apart, with twice as many participants receiving the potential vaccine as are receiving the saline control injection. Safety and efficacy will be assessed in all participants, and local and systemic reactions and immune responses will be assessed in 3,000 participants. Randomization will be stratified by age (≥18 to <65 years, and ≥ 65 years), with at least 25% of participants to be enrolled in the older age range.

Late-stage trials of AZD1222 are ongoing in the United Kingdom, Brazil, and South Africa, with trials anticipated to start in Japan and Russia. Combined with the US clinical trial, up to 50,000 participants globally will be included.Results from the late-stage trials are anticipated later this year, depending on local infection rates in clinical trial communities.

Promising early trial data

Interim results from the ongoing phase 1/2 COV001 trial were published in July and showed AZD1222 was well tolerated and generated robust immune responses against the SARS-CoV2 virus in all participants. The COV001 trial included 1077 healthy adult participants aged 18 to 55 years and evaluated a single dose of AZD1222 against a comparator meningococcal conjugate vaccine. In addition to the single dose, 10 adults also received 2 doses of AZD1222 1 month apart.2

In early data from trial, the vaccine prompted effective immune and T cell responses, resulting in a 4-fold increase in antibodies for SARS-CoV-2 in 95% of participants 1 month following receipt of the vaccine. All participants showed a T cell response that remained 2 months after receiving AZD1222. The study was published in The Lancet.

The US trial is funded by the Biomedical Advanced Development Authority (BARDA) of the US Department of Health and Human Services and the National Institute of Allergy and Infectious Diseases (NIAD) and led by AstraZeneca. The NIAID-supported COVID-19 Prevention Network also will participate in the trial.

“We are pleased that AZD1222 demonstrated safety and immunogenicity across all adult age groups and are proud to be collaborating with BARDA and NIAD to accelerate the development of this vaccine,” said Mene Panagalos, executive vice president of BioPharmaceuticals R&D, in the AstraZeneca press release. “Should clinical trials demonstrate the vaccine protects against COVID-19 disease and is approved for use, we will work hard to make it globally available in a fair and equitable manner as rapidly as possible.”

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Globally, as of September 2, 2020, there have been 25 816 820 confirmed cases of COVID-19, 858 381 deaths, and 17 120 092 recoveries.
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